/**
 * C Programming: A Modern Approach
 *
 * version: 2nd
 * author: K.N.King
 * http://knking.com/books/c2
 */

#include <stdio.h>

/**
 *
 */

int main(void) {
    int num;
    printf("Enter a two-digit number: ");
    scanf("%d", &num);
    if (num < 0 || num >= 100) {
        printf("Error: invalid num");
    }

    printf("The reversal is: %d%d\n", num % 10, num / 10);

    return 0;
}

/*
output:
Enter a two-digit number: 28
The reversal is: 82
*/